Organic light emitting diode display and method of manufacturing the same

ABSTRACT

A method of manufacturing an organic light emitting diode display includes forming a plurality of signal lines and a plurality of TFTs on a substrate, forming a passivation layer on the signal lines and the TFTs, forming a photosensitive layer having a plurality of openings on the passivation layer, etching the passivation layer using the photosensitive layer as a mask, forming a first electrode by depositing and etching a conductive layer on substantially the entire surface including the photosensitive layer, forming a light emitting member in portions of the openings, and forming a second electrode on the light emitting member and the photosensitive layer.

This application claims priority to Korean Patent Application No.10-2005-0102250 and Korean Patent Application No. 10-2005-0102254, bothfiled on Oct. 28, 2005, the contents of which in their entirety areherein incorporated by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an organic light emitting diode(“OLED”) display and a method of manufacturing the same.

(b) Description of the Related Art

Recently, thin and light-weight types of monitors and television setshave grown in popularity. Cathode ray tubes (“CRTs.”) have beenincreasingly replaced by liquid crystal displays (“LCDs”).

However, since the LCD is a non-emissive display device, a backlight isneeded in the construction of most LCD displays. Reflective LCDs may useambient light in order to display images, however they are not ideal forall applications. In addition, LCDs have limitations in their responsespeed and a viewing angle. Recently, as a display capable of overcomingthe aforementioned problems, an organic light emitting diode (“OLED”)display has been proposed.

An OLED display includes two electrodes and a light emitting layerinterposed therebetween. An electron injected from the one electrode anda hole injected from the other electrode are combined in the organiclight emitting layer to form an exciton, and the exciton dischargesenergy to emit light.

Since the OLED display is a self-emissive display device, a backlight isnot needed. Therefore, the OLED display has an advantage in powerconsumption and can be manufactured as a thinner structure. In addition,the OLED display has a faster response speed, wider viewing angle, andhigher contrast ratio than that of a comparable LCD.

An OLED display can be classified into a passive matrix OLED display andan active matrix OLED display according to its driving mode. Amongthese, an active matrix OLED display, which uses thin film transistors(“TFTs”) as a switching and driving device to drive each individualpixel, has advantages in that high resolution, low power consumption anda wide screen can be achieved.

An OLED display may further be classified into a bottom emission typedisplay, which emits light to an outside through a bottom substrate, ora top emission type display, which emits light to an outside through acommon electrode.

The active matrix OLED display primarily includes the TFT, an organiclight emitting member, and partition walls for defining the organiclight emitting members into individual pixels.

The partition walls protect the TFT, prevent a light emitting materialin a pixel from mixing with another light emitting material in anadjacent pixel, and prevent a short circuit between an anode and acathode.

However, since the partition walls are formed by a photolithographyprocess, the number of masks for the process increases, therebyincreasing manufacturing costs.

In addition, in order to improve the brightness of the OLED display, alight-emission amount per each unit pixel has to be increased, asopposed to the LCD where the output of the single backlight unit can beincreased.

In order to increase the amount of light emission, a method ofincreasing efficiency of a light-emitting material and a method ofincreasing a current applied to the unit pixel electrode have beenproposed.

However, there is a limitation to the efficiency obtainable from a lightemitting material. In addition, there is also a limit to the amount ofcurrent which can be applied to the unit pixel electrode in order tomaintain the lifetime and efficiency of the OLED display and TFT.

BRIEF SUMMARY OF THE INVENTION

An aspect of the present invention is to provide an organic lightemitting diode display and method of manufacturing the same that iscapable of reducing the number of masks, thereby simplifying themanufacturing processes, and at the same time increasing a lightemitting amount per unit pixel.

According to an exemplary embodiment of the present invention, there isprovided an organic light emitting diode display including; a substrate,a first signal line formed on the substrate, a second signal lineintersecting the first signal line, a plurality of thin film transistors(“TFTs”) formed on the substrate and electrically connected to the firstand second signal lines, a passivation layer formed on the TFTs, aphotosensitive layer formed on the passivation layer and having a firstopening, a first electrode connected to one of the TFTs and separatedfrom the photosensitive layer, a light emitting member formed on thefirst electrode and defined by the photosensitive layer, and a secondelectrode formed on the light emitting member.

The first electrode may have a smaller area than that of the firstopening.

A boundary of the first electrode may be disposed in the first opening,while contacting the light emitting member.

The first electrode may be disposed inside the first opening and isseparated from the photosensitive layer by about 1 μm to about 5 μm.

One of the TFTs and the first electrode may have side contact.

The first electrode may contact the substrate.

At least a portion of the light emitting member may overlap the TFTs.

The passivation layer may be removed from the first opening.

Portions of the photosensitive layer surrounding the first opening maybe used as partition walls.

The photosensitive layer may further include a second opening, and aconnecting member connecting a plurality of TFTs may be formed in thesecond opening and may be separated from the photosensitive layer.

The organic light emitting diode display may further include a firstinsulating member on the connecting member.

The passivation layer may be removed from the second opening.

The connecting member may contact the substrate.

The passivation layer and the photosensitive layer may include asingle-layered organic layer.

The organic layer may be made of a photo-curable material.

The organic light emitting diode display may further include a secondinsulating member formed in the first opening and having a thicknesswhich differs from that of the first opening.

The second insulating member may include the same material as that ofthe photosensitive layer.

The second insulating member may include at least one of a concave and aconvex portion.

According to another exemplary embodiment of the present invention,there is provided an organic light emitting diode display including; asubstrate, a first signal line formed on the substrate, a second signalline intersecting the first signal line, a plurality of TFTs formed onthe substrate and are electrically connected to the first and secondsignal lines, an insulating layer formed on the TFTs and having a firstportion and a second portion which is thinner than the first portion,the second portion having at least one of a concave portion and a convexportion, a first electrode formed on the insulating layer, a lightemitting member formed on the first electrode; and a second electrodeformed on the light emitting member.

The insulating layer may have a third portion which is thinner than thefirst portion, and the third portion may be formed on an end portion ofat least one of the first and second signal lines.

The first portion of the insulating layer may have an opening, and aconnecting member may be formed in the opening and a connecting memberis formed therein, wherein the connecting member may be separated fromthe insulating layer and connects a plurality of the TFTs.

According to an exemplary embodiment of the present invention, there isprovided a method of manufacturing an organic light emitting diodedisplay including; forming a plurality of signal lines and a pluralityof TFTs on a substrate, forming a passivation layer on the signal linesand the TFTs, forming a photosensitive layer having a plurality ofopenings on the passivation layer, etching the passivation layer usingthe photosensitive layer as a mask, forming a first electrode bydepositing a conductive layer on substantially the entire surfaceincluding the photosensitive layer and etching the conductive layer toform the first electrode, forming a light emitting member in portions ofthe openings, and forming a second electrode on the light emittingmember and the photosensitive layer.

In the etching of the passivation layer, portions of the TFTs may beexposed.

The method further may include forming an insulating member in theportions of the openings after the formation of the first electrode.

A shadow mask may be used in the formation of the insulating member.

In the formation of the first electrode, the first electrode may beformed to be spaced apart from the photosensitive layer.

The method may further include curing the photosensitive layer after theetching of the passivation layer.

In the formation of the passivation layer and the formation of thephotosensitive layer, the passivation layer and the photosensitive layermay be formed by depositing a single-layered organic layer.

In the etching the passivation layer, portions of the photosensitivelayer may be subject to a slit process developing.

In the formation of the photosensitive layer, the photosensitive layermay be patterned to have a first portion and a second portion which isthinner than the first portion, the second portion having at least oneof a concave portion and a convex portion.

A slit mask may be used in the formation of the photosensitive layer.

The formation of the photosensitive layer may further include forming athird portion in which the photosensitive layer is removed, and themethod of manufacturing an organic light emitting diode display mayfurther include forming an insulating member in the third portion afterthe formation of the first electrode.

According to another exemplary embodiment of the present invention,there is provided a method of manufacturing an organic light emittingdiode display including; forming a plurality of signal lines and aplurality of TFTs on a substrate, forming an organic insulating layer onthe signal lines and the TFTs, forming openings which expose portions ofthe TFTs by removing portions of the organic insulating layer, forming afirst electrode by depositing a conductive layer on substantially theentire surface including the organic insulating layer and etching theconductive layer to form the first electrode, forming a light emittingmember on portions of the openings, and forming a second electrode onthe light emitting member and the organic insulating layer.

The method may further include forming an insulating member in theportions of the openings after the formation the first electrode.

A shadow mask may be used in the formation of the insulating member.

In the formation of the first electrode, the first electrode may beformed be apart from the organic insulating layer.

According to another exemplary embodiment of the present invention,there is provided an organic light emitting diode display including; asubstrate, a first signal line formed on the substrate, a second signalline intersecting the first signal line, a plurality of TFTs formed onthe substrate and electrically connected to the first and second signallines, a passivation layer formed on the TFTs, partition walls formed onthe passivation layer and having a first opening, a first electrodecontacting at least one portion of the substrate in the first opening, alight emitting member formed on the first electrode and defined by thepartition walls, and a second electrode formed on the light emittingmember.

The first electrode may have an area which is smaller than that of thefirst opening.

The first electrode may be inside the first opening and may be separatedby about 1 μm to about 5 μm.

One of the TFTs and the first electrode may have side contact.

The passivation layer may be removed from the first opening.

The partition walls may have a second opening, and a connecting membermay be formed in the second opening and the light emitting diode displayfurther includes a connecting member formed in the second opening whichcontacts the substrate and connects a plurality of the TFTs.

The organic light emitting diode display may further include aninsulating member on the connecting member.

According to another aspect of the present invention, there is providedan organic light emitting diode display including; a substrate, a firstsignal line formed on the substrate, a second signal line intersectingthe first signal line, a switching TFT formed on the substrate andconnected to the first and second signal lines, a driving TFT connectedto the switching TFT, a driving voltage line connected to the drivingTFT, a passivation layer formed on the entire surface of the substrate,a photosensitive layer formed on the passivation layer and having afirst opening, a first electrode connected to the driving TFT andseparated from the photosensitive layer, a light emitting member formedon the first electrode and defined by the photosensitive layer, and asecond electrode formed on the light emitting layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinvention will become more apparent by describing exemplary embodimentsthereof in further detail with reference to the attached drawings, inwhich:

FIG. 1 is an equivalent circuit diagram of an exemplary embodiment of anorganic light emitting diode (“OLED”) display according to the presentinvention;

FIG. 2 is a top plan layout view of an exemplary embodiment of a pixelin an OLED display according to the present invention;

FIG. 3 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line III-III of FIG. 2;

FIGS. 4, 6, 8, 10, 12, and 14 are top plan views showing an exemplaryembodiment of a method of manufacturing the exemplary embodiment of anOLED display shown in FIGS. 2 and 3 according to the present invention;

FIG. 5 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line V-V of FIG. 4;

FIG. 7 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line VII-VII of FIG. 6;

FIG. 9 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line IX-IX of FIG. 8;

FIG. 11 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XI-XI of FIG. 10;

FIG. 13 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XIII-XIII of FIG. 12;

FIG. 15 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XV-XV of FIG. 14;

FIG. 16 is a top plan layout view of another exemplary embodiment of apixel in an OLED display according to the present invention;

FIG. 17 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XVII-XVII of FIG. 16;

FIGS. 18, 20, 22, 24, 26, and 28 are top plan views showing an exemplaryembodiment of a method of manufacturing the exemplary embodiment of anOLED display shown in FIGS. 16 and 17 according to the presentinvention;

FIG. 19 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XIX-XIX of FIG. 18;

FIG. 21 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XXI-XXI of FIG. 20;

FIG. 23 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XXIII-XXIII of FIG. 22;

FIG. 25 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XXV-XXV of FIG. 24;

FIG. 27 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XXVII-XXVII of FIG. 26;

FIG. 29 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XXIX-XXIX of FIG. 28;

FIG. 30A is a schematic view showing an exemplary embodiment of a pixelelectrode of which a surface is flat;

FIG. 30B is a schematic view showing an exemplary embodiment of a pixelelectrode of which a surface thereof has an embossed structure;

FIG. 30C is a cross-sectional view of the exemplary embodiment of apixel electrode taken along line A-A of FIG. 30B;

FIG. 30D is a schematic view showing an exemplary embodiment of a pixelelectrode of which a surface thereof has a rippled structure; and

FIG. 30E is a cross-sectional view of the exemplary embodiment of apixel electrode taken along line B-B of FIG. 30D.

DETAILED DESCRIPTION OF THE INVENTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likereference numerals refer to like elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes? and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother elements as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower”, can therefore, encompasses both an orientation of “lower” and“upper,” depending of the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Embodiments of the present invention are described herein with referenceto cross section illustrations that are schematic illustrations ofidealized embodiments of the present invention. As such, variations fromthe shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,embodiments of the present invention should not be construed as limitedto the particular shapes of regions illustrated herein but are toinclude deviations in shapes that result, for example, frommanufacturing. For example, a region illustrated or described as flatmay, typically, have rough and/or nonlinear features. Moreover, sharpangles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present invention.

Hereinafter, the present invention will be described in detail withreference to the accompanying drawings.

First, an organic light emitting diode (“OLED”) display according to anexemplary embodiment of the present invention will be described withreference to FIG. 1.

FIG. 1 is an equivalent circuit diagram of an exemplary embodiment ofthe OLED display according to the present invention;

Referring to FIG. 1, the exemplary embodiment of an OLED displayincludes a plurality of signal lines 121, 171 and 172 and a plurality ofpixels connected to the lines and arrayed substantially in a matrix.

The signal lines include a plurality of gate lines 121 for transmittinggate signals or scan signals, a plurality of data lines 171 fortransmitting data signals, and a plurality of driving voltage lines 172for transmitting driving voltages.

The gate lines 121 mainly extend in a row direction and aresubstantially parallel to each other, and the data lines 171 and thedriving voltage lines 172 mainly extend in a column direction and aresubstantially parallel to each other.

Each of the pixels includes a switching transistor Qs, a drivingtransistor Qd, a storage capacitor Cst, and the organic light emittingdiode (“OLED”) LD.

The switching transistor Qs includes a control terminal, an inputterminal, and an output terminal. The control terminal is connected tothe gate line 121, the input terminal is connected to the data line 171,and the output terminal is connected to the driving transistor Qd and afirst side of the storage capacitor Cst.

The switching transistor Qs transmits the data signals applied to thedata line 171 to the driving transistor Qd in response to the scansignals applied to the gate line 121.

The driving transistor Qd also includes a control terminal, an inputterminal, and an output terminal. The control terminal is connected tothe switching transistor Qs and the first side of the storage capacitorCst, the input terminal is connected to the driving voltage line 172 anda second side of the storage capacitor Cst, and the output terminal isconnected to the OLED LD.

The driving transistor Qd outputs an output current ILD, the magnitudeof which changes according to a voltage applied between the controlterminal and the output terminal thereof.

The capacitor Cst is connected between the control terminal and theinput terminal of the driving transistor Qd and is also connected to thedriving voltage line 172.

The capacitor Cst charges the data signals applied to the controlterminal of the driving transistor Qd and sustains the signals even whenthe switching transistor Qs is turned off.

The OLED LD includes an anode connected to the output terminal of thedriving transistor Qd and a cathode connected to a common voltage Vss.

The OLED LD emits light with different intensities according to themagnitude of the output current ILD of the driving transistor Qd. Aplurality of OLEDs LD may be arranged together so that an image can bedisplayed.

According to one exemplary embodiment, the switching transistor Qs andthe driving transistor Qd may be n-channel field effect transistors(“FETs”).

Alternative exemplary embodiments include configurations where at leastone of the switching transistor Qs and the driving transistor Qd may bea p-channel field effect transistor.

Although not herein described, variations in the connections between thetransistors Qs and Qd, the capacitor Cst, and the OLED LD are within thescope of the present invention.

Now, a detailed structure of the OLED display shown in FIG. 1 isdescribed in detail with reference to FIGS. 1, 2, and 3.

FIG. 2 is a top plan view of an exemplary embodiment of a pixel in theOLED display according to the present invention, and FIG. 3 is across-sectional view of the exemplary embodiment of an OLED displaytaken along line III-III of FIG. 2.

A plurality of gate conductors including a plurality of the gate lines121 which include a plurality of first control electrodes 124 a and aplurality of second control electrodes 124 b are formed on a insulatingsubstrate 110 made of transparent glass, plastic, or other similarsubstances.

The gate lines 121 mainly extend in a transverse direction to transmitthe gate signals.

Each of the gate lines 121 includes an end portion 129 having a largearea to connect to an external driving circuit (not shown) or otherlayers. The first control electrode 124 a extends in an upward directionextending from the gate line 121.

Alternative exemplary embodiments include configurations where a gatedriving circuit (now shown) for generating the gate signals isintegrated with the substrate 110. In such an exemplary embodiment, thegate line 121 may extend to directly connect to the gate drivingcircuit.

The second control electrode 124 b is separated from the gate line 121and includes a storage electrode 127. An exemplary embodiment of thestorage electrode is formed by extending a portion of the controlelectrode 124 b downward, turning to the right, and then extending itupward.

Exemplary embodiments of the gate conductors 121 and 124 b are made ofan aluminum-containing metal such as aluminum (Al) and an aluminumalloy, a silver-containing metal such as silver (Ag) and a silver alloy,a copper-containing metal such as copper (Cu) and copper alloy, amolybdenum-containing metal such as molybdenum (Mo) and a molybdenumalloy, chromium (Cr), tantalum (Ta), titanium (Ti), or other similarsubstance.

However, alternative exemplary embodiments include configurations wherethe gate lines 121 and 124 b have a multi-layered structure includingtwo conductive layers (not shown) having different physical propertiesfrom each other.

The lateral sides of the gate conductors 121 and 124 b are inclinedrelative to a surface of the substrate 110, and exemplary embodiments ofthe inclination angle may be in a range of about 30° to about 80°.

A gate insulating layer 140 made of a silicon nitride (“SiNx”), asilicon oxide (“SiOx”), or other similar substance is formed on the gateconductors 121 and 124 b.

A plurality of first semiconductors 154 a and a plurality of secondsemiconductors 154 b, which are made of a hydrogenated amorphous silicon(abbreviated to a-Si) or a polysilicon, are formed on a gate insulatinglayer 140.

The first semiconductor 154 a is disposed on the first control electrode124 a, and the second semiconductor 154 b is disposed on the secondcontrol electrode 124 b.

A plurality pairs of first ohmic contacts 163 a and 165 a and aplurality pairs of second ohmic contacts 163 b and 165 b are formed onthe first and second semiconductors 154 a and 154 b, respectively.

The ohmic contacts 163 a, 163 b, 165 a, and 165 b are island-shaped andare made of a silicide or an n+ hydrogenated amorphous silicon or othersimilar substances which are highly doped with n-type impurities such asa phosphorus (P) or other similar substances.

A plurality of data conductors including a plurality of the data lines171, a plurality of the driving voltage lines 172, and a plurality offirst and second output electrodes 175 a and 175 b are formed on theohmic contacts 163 a, 163 b, 165 a, and 165 b and the gate insulatinglayer 140.

The data lines 171 extend in a longitudinal direction to intersect thegate lines 121 and transmit the data signals.

Each of the data lines 171 includes an input electrode 173 a extendingtoward the first control electrode 124 a and an end portion 179 having alarge area to connect to an external driving circuit (not shown) orother layers.

In an exemplary embodiment where a data driving circuit (not shown) forgenerating the data signals is integrated with the substrate 110, thedata lines 171 may extend to directly connect to the data drivingcircuit.

The driving voltage lines 172 extend in a longitudinal direction,substantially parallel to the data lines 171, to intersect the gatelines 121 and transmit the driving voltages.

Each of the driving voltage lines 172 includes a second input electrode173 b extending toward the second control electrode 124 b.

The driving voltage line 172 overlaps with the storage electrode 127.

The first and second output electrodes 175 a and 175 b are separatedfrom each other, and are also separated from the data lines 171 and thedriving voltage lines 172, respectively.

Each pair of the first input electrode 173 a and the first outputelectrode 175 a are disposed opposite each other with respect to thefirst control electrode 124 a, and each pair of the second inputelectrodes 173 b and the second output electrodes 175 b are disposedopposite each other with respect to a second control electrode 124 b.

Exemplary embodiments of the data conductors 171, 172, 175 a, and 175 bare made of aluminum (Al), molybdenum (Mo), chromium (Cr), or arefractory metal such as tantalum (Ta) and titanium (Ti). Alternativeexemplary embodiments include configurations where the data conductors171, 172, 175 a, and 175 b may have a multi-layered structure which isconstructed with a refractory metal layer (not shown) and a lowresistance conductive layer (not shown).

The lateral sides of the data conductors 171, 172, 175 a, and 175 b maybe inclined relative to the surface of the substrate 110, and theinclination angle may be in a range of about 30° to about 80°, similarto those of the gate conductors 121 and 124 b.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175 b, the exposed portions of the semiconductors 154 a and 154b, the exposed portions of the ohmic contacts 163 a, 163 b, 165 a and165 b, and the gate insulating layer 140.

The passivation layer 180 is made of an inorganic material or an organicmaterial or the like. Exemplary embodiments of the inorganic materialare silicon nitride (“SiNx”) and silicon oxide (“SiOx”), and anexemplary embodiment of the organic material is polyacryl.

Alternative exemplary embodiments include the configuration where thepassivation layer 180 includes a double-layered structure of aninorganic layer and an organic layer.

A plurality of contact holes 182 which expose the end portions 179 ofthe data lines 171 are formed in the passivation layer 180, and aplurality of contact holes 181 which expose the end portions 129 of thegate lines 121 are formed in the passivation layer 180 and the gateinsulating layer 140.

In addition, a contact hole 185 b which exposes the second outputelectrode 175 b is formed in the passivation layer 180, and a contacthole 185 a which simultaneously exposes a lateral side of the firstoutput electrode 175 a, a lateral side of the second control electrode124 b, and the substrate disposed therebetween is formed in thepassivation layer 180 and the gate insulating layer 140.

A photosensitive layer 361 is formed on the passivation layer 180.

The photosensitive layer 361 has an opening 365 which exposes thecontact hole 185 b and the second output electrode 175 b, an opening 367which simultaneously exposes the contact hole 185 a, the second controlelectrode 124 b, and the first output electrode 175 a, and openings 368and 369 that expose the end portion 129 of the gate line 121 and the endportion 179 of the data line 171.

A portion of the photosensitive layer 361 surrounding the opening 365 isused as a partition wall to be described further below.

The portions of the photosensitive layer 361 disposed on the end portion129 of the gate line 121 and the end portion 179 of the data lines 171are thinner than other portions to allow for an easier connection to anexternal circuit (not shown).

The photosensitive layer 361 may be made of an organic material havingthermal resistance and liquid resistance. Exemplary embodiments of theorganic material include an acryl resin and a polyimide resin or othersimilar substance. Exemplary embodiments of the inorganic materialinclude a silicon oxide (“SiOx”) and a titanium oxide (“TiOx”) or othersimilar substances. Alternative exemplary embodiments includeconfigurations where the photosensitive layer 361 may have more than twolayers.

In addition, the photosensitive layer 361 may be made of aphotosensitive material containing a black pigment. In this case, thephotosensitive layer 361 serves as a light-blocking member.

The photosensitive layer 361 may be used as a mask to form the contactholes 181, 182, 185 a, and 185 b in the passivation layer 180 and thegate insulating layer 140.

In the exemplary embodiment where the passivation layer 180 is made ofthe organic material, the passivation layer 180 and the photosensitivelayer 361 may be formed to constitute a single-layered photosensitiveorganic insulating layer.

The photosensitive organic insulating layer comprising the passivationlayer 180 and the photosensitive layer 361 includes a photo-curablematerial and is disposed in the same manner as if it had been disposedas two separate layers as discussed above.

A plurality of pixel electrodes 191 are formed in the opening 365 whichis defined by the photosensitive layer 361.

The pixel electrode 191 contacts the second output electrode 175 b andthe substrate 110.

The second electrode 175 b and the pixel electrode 191 have sidecontact. Portions of the gate insulating layer 140 disposed under thepixel electrode 191 are removed, so that the pixel electrode 191 and thesubstrate 110 directly contact each other.

As described above, since portions of the gate insulating layer 140disposed under the pixel electrode 191 are removed, light transmissivityfor a bottom emission type display is increased.

The pixel electrode 191 is separated by a predetermined distance fromthe boundary of the opening 365. For example, the distance may be about1 μm to about 5 μm.

As a result, an end portion of the pixel electrode 191 is exposedthrough the opening 365.

A plurality of connecting members 85 are formed in the opening 367 whichis defined by a gap in the photosensitive layer 361.

The connecting member 85 is connected to the second control electrode124 b and the first output electrode 175 a through the contact hole 185a.

In this case, the second control electrode 124 b and one side of theconnecting member 85 have side contact, and the first output electrode175 a and the other side of the connecting member 85 have side contact.

In addition, the connecting member 85 contacts the substrate 110 betweenthe second control electrode 124 b and the first output electrode 175 a.

The connecting member 85 is separated by a predetermined distance fromthe boundary of the opening 367. For example, the distance may be about1 μm to about 5 μm.

As a result, an end portion of the connecting member 85 is exposedthrough the opening 367.

Contact assistants 81 and 82 are formed in the openings 368 and 369which are defined by gaps in the photosensitive layer 361.

The contact assistants 81 and 82 are connected to the end portions 129and 179 of the gate and data lines 121 and 171 through the contact holes181 and 182, respectively. Therefore, the contact assistants 81 and 82have a function of enhancing adhesiveness of the end portions 129 and179 of the gate and data lines 121 and 171 to the external devices andprotecting the end portions 129 and 179.

Exemplary embodiments of the pixel electrode 191, the connecting member85, and the contact assistants 81 and 82 may be made of a transparentconductor such as indium tin oxide (“ITO”) and indium zinc oxide (“IZO”)or other similar substances. In a top emission type of display, thepixel electrode 191, the connecting member 85, and the contactassistants 81 and 82 may be made of an opaque conductor such as aluminum(Al) and an aluminum alloy, gold (Au), platinum (Pt), nickel (Ni),copper (Cu), and tungsten (W), which all have high work functions.

An insulating member 40 is formed on the connecting member 85.

The insulating member 40 may be made of a silicon nitride (“SiNx”) or asilicon oxide (“SiOx”) and may entirely cover the connecting member 85for the protection thereof.

An organic light emitting member 370 is formed in the opening 365defined by the gap in the photosensitive layer 361.

The organic light emitting member 370 includes an emitting layer (notshown) for emitting light, and may have a multi-layered structureincluding an auxiliary layer (not shown) for enhancing a light emittingefficiency of the emitting layer.

The emitting layer may be made of an organic material, which emits lightof one of primary colors such as red, green, and blue. The emittinglayer may include a polyfluorene derivative, a(poly)paraphenylenevinylene derivative, a polyphenylene derivative, apolyfluorene derivative, a polyvinylcarbazole derivative, apolythiophene derivative, or a polymer thereof doped with aperylene-based pigment, a cumarine-based pigment, a rhodamine-basedpigment, rubrene, perylene, 9,10-diphenylanthracene,tetraphenylbutadiene, Nile red, coumarin, quinacridone.

A color OLED display displays a desired image by a spatial combinationof the primary colors emitted from the emitting layer.

Exemplary embodiments of the auxiliary layers include an electrontransport layer (not shown) and a hole transport layer (not shown) whichbalance electrons and holes, and an electron injecting layer (not shown)and an hole injecting layer (not shown) which enhance injection of theelectrons and the holes. The auxiliary layers may include one or morelayers selected from the aforementioned layers.

The hole transport layer and the hole injection layer may be made of amaterial having a work function which is between the work functions ofthe pixel electrode 191 and the emitting layer. The electron transportlayer and the electron injection layer may be made of a material havinga work function which is between the work functions of a commonelectrode 270 and the emitting layer.

Exemplary embodiments of the hole transport layer or the hole injectionlayer may be made ofpoly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (“PEDOT:PSS”) orother similar substances.

The common electrode 270 is formed on the entire surface comprising theorganic light emitting member 370 and the insulating member 40.

The common electrode 270 and the pixel electrode 191 supply current tothe organic light emitting member 370.

The insulating member 40 insulates the connecting member 85 from thecommon electrode 270.

The common electrode 270 may be made of an opaque conductive materialwhich has good electron injection characteristics and does not influencethe organic material. Exemplary embodiments of the common electrode 270may be made of an aluminum-based metal, barium (Ba), or other similarsubstances.

In addition, in the top emission type display, the common electrode 270may be made of a transparent or a translucent conductive material.Exemplary embodiments of the common electrode 270 may be asingle-layered structure including indium tin oxide (“ITO”), indium zincoxide (“IZO”), aluminum (Al), and silver (Ag) having a thickness ofabout 50 to 100 Å, or other similar substances. Alternative exemplaryembodiments include configurations where the common electrode 270 may bea multi-layered structure including Ca—Ag, LiF—Al, Ca—Ba, Ca—Ag—ITO, orother similar substances.

In the OLED display, the first control electrode 124 a connected to thegate line 121, the first input electrode 173 a connected to the dataline 171, and the first output electrode 175 a together with the firstsemiconductor 154 a constitute the switching thin film transistor(switching TFT) Qs, and the channel thereof is formed in the firstsemiconductor 154 a between the first input electrode 173 a and thefirst output electrode 175 a.

The second control electrode 124 b connected to the first outputelectrode 175 a, the second input electrode 173 b connected to thedriving voltage line 172, and the second output electrode 175 bconnected to the pixel electrode 171 together with the secondsemiconductor 154 b constitute the driving thin film transistor (drivingTFT) Qd, and the channel thereof is formed in the second semiconductor154 b between the second input electrode 173 b and the second outputelectrode 175 b.

In the present exemplary embodiment, a single switching TFT and a singledriving TFT are employed. However, alternative exemplary embodimentsinclude configurations where at least one TFT and a plurality of wirelines for driving the TFTs may be further included. Accordingly, evenwhen the OLED and the driving transistor Qd are driven for long periodsof time, deterioration in the performance of the OLED and the drivingtransistor Qd may be prevented, reduced or compensated for, so that alifetime of the OLED display is prevented from being shortened. Theadditional TFT and the wire can compensate for the changes of thethreshold voltage depending on time. Thus, depending on the time,deterioration of the driving transistor Qd and the OLED can beprevented.

The pixel electrode 191, the organic light emitting member 370, and thecommon electrode 270 constitute the OLED LD. The pixel electrode 191 mayserve as the anode, and the common electrode 270 may serve as thecathode in the top emission type display. On the contrary, in the bottomemission type display the pixel electrode 191 may serve as the cathode,and the common electrode 270 may serve as the anode.

The storage electrode 127 and the driving voltage line 172 overlappingeach other constitute the storage capacitor Cst.

In the exemplary embodiment where the semiconductors 154 a and 154 b aremade of a polysilicon, the semiconductors 154 a and 154 b include anintrinsic region (not shown) facing the control electrodes 124 a and 124b and an extrinsic region disposed at both sides of the intrinsicregion.

In such an exemplary embodiment the extrinsic region is electricallyconnected to the input electrode 173 a and 173 b and the outputelectrodes 175 a and 175 b, and the ohmic contacts 163 a, 163 b, 165 a,and 165 b may be omitted.

In another exemplary embodiment, the control electrodes 124 a and 124 bmay be disposed on the semiconductors 154 a and 154 b. In this exemplaryembodiment, the gate insulating layer 140 is also disposed between thesemiconductors 154 a and 154 b and the control electrodes 124 a and 124b.

The data conductors 171, 172, 173 a, 173 b, 175 b and 175 b are disposedon the gate insulating layer 140 and are electrically connected to thesemiconductors 154 a and 154 b through contact holes (not shown) formedin the gate insulating layer 140.

In yet another exemplary embodiment, the data conductors 171, 172, 173a, 173 b, 175 a and 175 b may be disposed under the semiconductors 154 aand 154 b to be electrically connected to the semiconductors 154 a and154 b disposed thereon.

Now, a method of manufacturing the OLED display shown in FIGS. 2 and 3will be described in detail with reference to FIGS. 4 to 15.

FIGS. 4, 6, 8, 10, 12, and 14 are top plan views showing an exemplaryembodiment of a method of manufacturing the exemplary embodiment of anOLED display shown in FIGS. 2 and 3 according to the present invention,FIG. 5 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line V-V of FIG. 4, FIG. 7 is a cross-sectional viewof the exemplary embodiment of an OLED display taken along line VII-VIIof FIG. 6, FIG. 9 is a cross-sectional view of the exemplary embodimentof an OLED display taken along line IX-IX of FIG. 8, FIG. 11 is across-sectional view of the exemplary embodiment of an OLED displaytaken along line XI-XI of FIG. 10, FIG. 13 is a cross-sectional view ofthe exemplary embodiment of an OLED display taken along line XIII-XIIIof FIG. 12, and FIG. 15 is a cross-sectional view of the exemplaryembodiment of an OLED display taken along line XV-XV of FIG. 14.

Referring to FIGS. 4 and 5, a plurality of gate conductors are formed ona substrate 110. The plurality of gate conductors include a plurality ofgate lines 121 which include first control electrodes 124 a and endportions 129, and a plurality of second control electrodes 124 b whichinclude storage electrodes 127.

Next, referring to FIGS. 6 and 7, a gate insulating layer 140, anintrinsic a-Si layer, and an extrinsic a-Si layer are sequentiallydeposited on the gate conductor and the substrate, and the extrinsica-Si layer and the intrinsic a-Si layer are patterned by a lithographyand etching process to form a plurality of extrinsic semiconductors 164a and 164 b and a plurality of first and second semiconductors 154 a and154 b.

Next, although not shown in FIGS. 6 and 7, data conductors are formed.The data conductors include a plurality of data lines 171 which includefirst input electrodes 173 a and end portions 179, driving voltage lines172 which include second input electrodes 173 a, and a plurality offirst and second output electrodes 175 a and 175 b.

Next, referring to FIGS. 8 and 9, when exposed portions of the extrinsicsemiconductors 164 a and 164 b which are not covered with the dataconductors 171, 172, 175 a, and 175 b are removed, ohmic contacts 163 a,165 a, 163 b, and 165 b are formed, and portions of the first and secondsemiconductors 154 a and 154 b which are disposed under the extrinsicsemiconductors 164 a and 164 b are exposed.

Next, referring to FIGS. 10 and 11, a passivation layer 180 is depositedon the entire surface of the substrate 110. In one exemplary embodimentthe passivation layer 180 is deposited by a chemical vapor deposition(“CVD”) process or another similar process.

Next, a photosensitive organic layer is coated on the passivation layer180 by using a spin coating process or another similar process, and aphotosensitive layer 361 is formed to have openings 365, 367, 368, and369 by performing exposing and developing processes on thephotosensitive organic layer.

Here, the photosensitive layer 361 located on the end portions 129 and179 of the gate line 121 and the data line 171, respectively, are formedto be thin by performing a slit process.

Next, referring to FIGS. 12 and 13, a plurality of contact holes 181,182, 185 a, and 185 b are formed by etching the passivation layer 180and the gate insulating layer 140 by using the photosensitive layer 361as a mask.

Here, the photosensitive layer 361 is cured, so that portions thereofare used as partition walls.

As described above, in the present exemplary embodiment, after thepassivation layer 180 is formed, the photosensitive layer 361 used asthe partition walls is formed to pattern the passivation layer 180 byusing the photosensitive layer 361 as the mask. As a result, thephotolithography process to form the contact holes 181, 182, 185 a, and185 b in the passivation layer 180 may be omitted, thereby reducing thenumber of masks required in the manufacture of the display andsimplifying the manufacturing processes.

In the present exemplary embodiment, the passivation layer 180 and thephotosensitive layer 361 are formed in separate processes. However, inan alternative exemplary embodiment where the passivation layer 180 ismade of an organic material, the passivation layer 180 and thephotosensitive layer 361 may be formed to constitute a single-layeredphotosensitive organic insulating layer.

In such an alternative exemplary embodiment, the photosensitive organicinsulating layer is coated on the data conductors 171, 172, 175 a, and175 b, the exposed portions of the semiconductors 154 a and 154 b, andthe gate insulating layer 140. Then, the openings 365, 367, 368, and 369are formed in the photosensitive organic layer by performing theexposing and developing processes at one time.

Therefore, depositing and etching processes on the passivation layer 180may be omitted, so that it is possible to simplify the manufacturingprocesses.

Next, after indium tin oxide (“ITO”) is deposited on the photosensitivelayer 361 and the substrate 110 and is patterned, a plurality of pixelelectrodes 191, a plurality of connecting members 85, and a plurality ofcontact assistants 81 and 82 are formed.

Next, a shadow mask (not shown) having a predetermined opening portionis placed above the substrate 110, and an insulating material such as asilicon nitride (“SiNx”) or the like is deposited.

Here, the opening portion of the shadow mask is placed above the opening367 which exposes the connecting member 85, so that an insulating member40 may be formed only on the opening 367.

Next, referring to FIGS. 14 and 15, a light emitting member 370including a hole transport layer (now shown) and an emitting layer (nowshown) are formed in the opening 365.

The light emitting member 370 may be formed by a solution process suchas an inkjet printing process or a deposition. The present exemplaryembodiment uses the inkjet printing process. In the inkjet printingprocess, an ink is dropped into the opening 365 by moving an inkjet head(not shown) across the display. In this case, after each layer isformed, a drying process is performed.

As described above, the boundary of the opening 365 which defines thelight emitting member 370 is formed beyond the pixel electrode 191.Therefore, in the case where the light emitting member 370 is formed byusing the inkjet printing process, the light emitting member 370 fluidlyfills the boundaries of the opening 365. The light emitting member 370can thus be formed to be uniformly adhesive to the pixel electrode 191.Accordingly, it is possible to increase light emitting efficiencybecause the light emitting member 370 makes contact throughout the pixelelectrode.

Next, referring to FIGS. 2 and 3, a common electrode 270 is formed onthe photosensitive layer 361 and the light emitting member 370.

As described above, the photosensitive layer 361 used as the partitionwalls serves as the mask to etch the lower layers thereof, so that it ispossible to reduce the number of masks and to simplify the manufacturingprocesses.

In addition, the passivation layer 180 is not formed under the pixelelectrode 191, so that it is possible to increase light transmissivityin a bottom emission type display by preventing the passivation layer180 from absorbing, scattering or reflecting the light from the lightemitting member 370.

Now, a structure of another exemplary embodiment of an OLED displayaccording to the present invention will be described in detail withreference to FIGS. 1, 16, and 17.

Like reference numerals denote like elements, and descriptions ofpreviously-described components are omitted.

FIG. 16 is a top plan layout view of another exemplary embodiment of anOLED display according to the present invention, and FIG. 17 is across-sectional view of the exemplary embodiment of an OLED displaytaken along line XVII-XVII of FIG. 16.

A plurality of gate conductors including a plurality of second controlelectrodes 124 b and a plurality of gate lines 121 having first controlelectrodes 124 a are formed on an insulating layer 110.

A gate insulating layer 140 made of a silicon nitride (“SiNx”) or asilicon oxide (“SiOx”) or another similar substance is formed on thegate conductors 121 and 124 b.

A plurality of first and second semiconductors 154 a and 154 b, whichare made of hydrogenated amorphous silicon (a-Si) or polysilicon, areformed on the gate insulating layer 140.

The first semiconductor 154 a is disposed on the first control electrode124 a, and the second semiconductor 154 b is disposed on the secondcontrol electrode 124 b.

A plurality of pairs of first ohmic contacts 163 a and 165 a and aplurality of pairs of second ohmic contacts 163 b and 165 b are formedon the first and second semiconductors 154 a and 154 b, respectively.

A plurality of data conductors including a plurality of the data lines171, a plurality of the driving voltage lines 172, and a plurality offirst and second output electrodes 175 a and 175 b are formed on theohmic contacts 163 a, 163 b, 165 a, and 165 b and the gate insulatinglayer 140

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175 b, exposed portions of the semiconductors 154 a and 154 b,exposed portions of the ohmic contacts 163 a, 163 b, 165 a and 165 b andthe gate insulating layer 140.

A plurality of contact holes 182 and 185 b which expose an end portion179 of the data line 171 and the second output electrode 175 b areformed on the passivation layer 180.

In addition, a contact hole 181 which exposes an end portion 129 of thegate line 121 and a contact hole 185 a which simultaneously exposes thefirst output electrode 175 a and the second control electrode 124 b areformed in the passivation layer 180 and the gate insulating layer 140.

An insulating layer 360 is formed on the passivation layer 180. Theinsulating layer 360 includes a first portion 361 and second and thirdportions 362 and 363, respectively, which are both thinner than thefirst portion 361.

The first portion 361 includes partition walls for defining a lightemitting material therein, and has an opening 367 which simultaneouslyexposes the second control electrode 124 b and the first outputelectrode 175 a.

The second portion 362 is surrounded by the first portion 361 and isthinner than the first portion 361. The surface of the second portion362 has an uneven shape in which concave and convex portions arealternately arrayed.

In addition, the contact hole 185 b is exposed between the first andsecond portions 361 and 362, and the second output electrode 175 b isexposed therethrough.

The third portion 363 has openings 368 and 369 which expose the endportions 129 and 179 of the gate line and data line 121 and 171,respectively. The third portion 363 is thinner than the first portion361 to easily connect to an external circuit.

The insulating layer 360 may be made of a photosensitive organicinsulating material having thermal and solvent resistance. Exemplaryembodiments of such a photosensitive organic insulating material includean acrylic resin and a polyimide resin or other similar substances.Exemplary embodiments of the insulating layer 360 may also include aninorganic material such as a silicon oxide (“SiOx”) and a titanium oxide(“TiOx”) or other similar substances. Alternative exemplary embodimentsalso include configurations where the insulating layer 360 may beconstructed with two or more layers.

In addition, the insulating layer 360 may be made of a photosensitivematerial containing a black pigment. In this case, the insulating layer360 serves as a light-blocking member.

The first, second, and third portions 361, 362, and 363 of theinsulating layer 360 may serve as a photosensitive layer to be used as amask to form the contact holes 181, 182, 185 a, and 185 b in thepassivation layer 180 and the gate insulating layer 140 disposed underthe insulating layer 360.

A plurality of pixel electrodes 191 are formed on the second portion 362of the insulating layer 360.

The pixel electrodes 191 are connected to the second output electrode175 b through the contact hole 185 b, and a surface of the pixelelectrode has a shape embossed on the insulating layer 360 to match theconcave-convex shape of the second portion 362.

As described above, in a case where the pixel electrodes 191 have theembossed shape, a surface area thereof increases. Therefore, an emissionarea also increases.

Accordingly, as compared with a flat structure, the embossed structurehas a larger emission area in terms of the same aperture ratio.

For further explanation, examples are provided with reference to FIGS.30A to 30E.

FIG. 30A is a schematic view showing an exemplary embodiment of a pixelelectrode of which a surface is flat, FIG. 30B is a schematic viewshowing an exemplary embodiment of a pixel electrode of which thesurface has an embossed structure, FIG. 30C is a cross-sectional view ofthe exemplary embodiment of a pixel electrode taken along line A-A ofFIG. 30B, FIG. 30D is a schematic view showing an exemplary embodimentof a pixel electrode of which the surface has a rippled structure, andFIG. 30E is a cross-sectional view of the exemplary embodiment of apixel electrode taken along line B-B of FIG. 30D.

In FIGS. 30A to 30D, P denotes a unit pixel and L denotes an emissionregion of the unit pixel.

Here, the unit pixel has an area of a*b, and the emission region has anarea of c*d. Hereinafter, for the convenience of calculation, thelengths a, b, c, and d are assumed to be 100, 300, 60, and 200,respectively. However, these lengths are not meant to limit the presentinvention but are provided to clarify the principle of increased contactarea between the pixel electrode 191 and the organic light emittingmember 370.

Referring to FIG. 30A, the surface of the unit pixel 191 is flat. Forexample, one unit pixel has an area of 100*300=30,000, and the emissionregion of the unit pixel has an area of 60*200=12,000. For a flatsurface, the emission area has the same surface area as that of theemission region, and a ratio of surface area of the emission region tothe surface area of the unit pixel is 12,000/30,000=40%.

On the other hand, referring to FIG. 30B, the surface of the unit pixel191 has the embossed structure. For example, a radius of the embossedhemisphere formed in the emission region L is assumed to be 10, and 30individual hemispheres are formed within the emission region L.

In this case, the surface area (2πr²) of the hemisphere of the embossedball is 200π, so that a total surface area of the emission region L is30*(400−10²π+200π)=12,000+3,000π.

Therefore, the emission area increases by about 3,000π compared to thatin the flat structure, so that the ratio of the emission region to thepixel increases up to (12,000+3,000π)/30,000≈71%.

Similarly, referring to FIG. 30D, the surface of the unit pixel 191 hasa rippled structure. For example, in the rippled structure, upward anddownward half cylinders with radiuses of 5 are alternately arrayed. Inthis case, the circumference (πr) of the half cylinder is 5π, and 6 halfcylinders can be formed, so that a total surface area of the rippledstructure is 6*5π*200=6,000π.

Therefore, the ratio of the emission region to the pixel is6,000π/30,000≈62.8%.

The previous explanation is for a better understanding of the principlesinvolved, the embossed and rippled structures are exemplified but theydo not limit the present invention as various uneven structures whichare capable of increasing the surface area may be employed to obtain thesame results.

As described above, the embossed structure of the pixel electrode 191has a large emission surface area as compared with a flat structure interms of the same aperture ratio.

Referring again to FIGS. 16 and 17, a plurality of connecting members 85are formed in the openings 367 of the first portions 361.

The connecting members 85 are connected to the second control electrode124 b and the first output electrode 175 a through the contact hole 185a.

In this exemplary embodiment the second control electrode 124 b and oneside of the connecting member 85 have side contact, and the first outputelectrode 175 a and the other side of the connecting member 85 have sidecontact.

In addition, the connecting member 85 contacts the substrate 110 betweenthe second control electrode 124 b and the first output electrode 175 a.

The connecting member 85 is separated by a predetermined distance fromthe boundary of the opening 367. For example, the distance may be about1 to 5 μm.

As a result, an end portion of the connecting member 85 is exposedthrough the opening 367.

Contact assistants 81 and 82 are formed in the openings 368 and 369 ofthe third portion 363.

The pixel electrode 191, the connecting member 85, and the contactassistants 81 and 82 may be made of a transparent conductor such as ITOand IZO or another similar substance. In a top emission type display,the pixel electrode 191, the connecting member 85, and the contactassistants 81 and 82 may be made of an opaque conductor such as aluminum(Al) and an aluminum alloy, gold (Au), platinum (Pt), nickel (Ni),copper (Cu), and tungsten (W), which have high work functions.

An insulating member 40 is formed on the connecting member 85.

The insulating member 40 may be made of a silicon nitride (“SiNx”) or asilicon oxide (“SiOx”) and to entirely cover the connecting member 85for the protection thereof.

An organic light emitting member 370 is formed on the pixel electrode191.

The organic light emitting member 370 includes an emitting layer (notshown) for emitting light, and may have a multi-layered structureincluding an auxiliary layer (not shown) for enhancing light emittingefficiency of the emitting layer.

The common electrode 270 is formed on the entire surface covering theorganic light emitting member 370 and the insulating member 40.

The common electrode 270 and the pixel electrode 191 supply current tothe organic light emitting member 370.

The insulating member 40 insulates the connecting member 85 from thecommon electrode 270.

Now, a method of manufacturing the OLED display shown in FIGS. 16 and 18will be described in detail with reference to FIGS. 18 to 29.

FIGS. 18, 20, 22, 24, 26, and 28 are top plan views showing steps of anexemplary embodiment of a method of manufacturing the exemplary OLEDdisplay shown in FIGS. 16 and 17 according to the present invention.FIG. 19 is a cross-sectional view of the exemplary embodiment of an OLEDdisplay taken along line XIX-XIX of FIG. 18. FIG. 21 is across-sectional view of the exemplary embodiment of an OLED displaytaken along line XXI-XXI of FIG. 20. FIG. 23 is a cross-sectional viewof the exemplary embodiment of an OLED display taken along lineXXIII-XXIII of FIG. 22. FIG. 25 is a cross-sectional view of theexemplary embodiment of an OLED display taken along line XXV-XXV of FIG.24. FIG. 27 is a cross-sectional view of the exemplary embodiment of anOLED display taken along line XXVII-XXVII of FIG. 26. FIG. 29 is across-sectional view of the exemplary embodiment of an OLED displaytaken along line XXIX-XXIX of FIG. 28.

Referring to FIGS. 18 and 19, gate conductors are formed on a substrate110. The gate conductors include a plurality of gate lines 121, whichfurther include first control electrodes 124 a and end portions 129, anda plurality of second control electrodes 124 b, which further includestorage electrodes 127.

Next, referring to FIGS. 20 and 21, a gate insulating layer 140, anintrinsic a-Si layer, and an extrinsic a-Si layer are sequentiallydeposited on the gate conductor and the substrate, and the extrinsica-Si layer and the intrinsic a-Si layer are patterned by lithography andetching to form a plurality of extrinsic semiconductors 164 a and 164 band a plurality of first and second semiconductors 154 a and 154 b.

Next, data conductors which include a plurality of data lines includingfirst input electrodes 173 a and end portions 179, driving voltage lines172 including second input electrodes 173 a, and a plurality of firstand second output electrodes 175 a and 175 b are formed on the gateinsulating layer 140 and extrinsic semiconductors 164 a and 164 b.

Next, referring to FIGS. 22 and 23, exposed portions of the extrinsicsemiconductors 164 a and 164 b which are not covered with the dataconductors 171, 172, 175 a and 175 b are removed, so that ohmic contacts163 a, 165 a, 163 b, and 165 b are formed, and portions of the first andsecond conductors 154 a and 154 b which are disposed under the extrinsicsemiconductors 164 a and 164 b are exposed.

Next, referring to FIGS. 24 and 25, a passivation layer 180 is depositedon the entire surface of substrate 110 by using a chemical vapordeposition process or the like.

Next, a photosensitive organic solution is coated on the passivationlayer 180 by using a spin coating process or the like, and aphotosensitive layer 360 including first, second, and third portions361, 362, and 363 is formed.

Here, the first, second, and third portions 361, 362, and 363 are formedby one mask. The mask has a lattice shape to form a concave-convex shapein the second portion 362, and has a slit structure to form the thinthird portion 363.

Next, referring to FIGS. 26 and 27, the passivation layer 180 and thegate insulating layer 140 are etched using the photosensitive layer 360as the mask to form a plurality of contact holes 181, 182, 185 a, and185 b.

Next, the photosensitive layer 360 is cured.

As described above, in this exemplary embodiment, after the passivationlayer 180 is formed, the photosensitive layer 360 is formed, and thepassivation layer is patterned using the photosensitive layer 360 as amask.

Accordingly, a photolithography process for forming the contact holes181, 182, 185 a, and 185 b in the passivation layer 180 may be omitted,so that it is possible to reduce the number of masks and therebysimplify the manufacturing processes.

Next, ITO is deposited on the photosensitive layer 360 and the substrate110, to form a plurality of pixel electrodes 191, a plurality ofconnecting members 85, and a plurality of contact assistants 81 and 82.

Next, a shadow mask (not shown) having a predetermined shaped openingportion is placed above the substrate 110, and an insulating materialsuch as a silicon nitride (SiNx) or the like is deposited.

Here, the opening portion of the shadow mask is disposed on the opening367 which exposes the connecting member 85, so that an insulating member40 is formed only on the opening 367.

Next, referring to FIGS. 28 and 29, a light emitting member 370including a hole transport layer (now shown) and an emitting layer (nowshown) is formed on the opening 365.

The light emitting member 370 may be formed by a solution process.Exemplary embodiments of such a solution process are an inkjet printingprocess or a deposition process. This exemplary embodiment uses theinkjet printing process. In the inkjet printing process, an ink issprayed into the opening 365 by shifting an inkjet head (not shown). Inthis exemplary embodiment, after each layer is formed, a drying processis performed.

Next, referring to FIGS. 16 and 17, a common electrode 270 is formed onthe photosensitive layer 360 and the light emitting member 370.

In this exemplary embodiment, the concave-convex structures are formedby the aforementioned methods. However, various methods of forming theconcave-convex shape may be employed. Alternative exemplary embodimentsinclude the configurations in which an organic layer is additionallyformed before the pixel electrode is formed and then the pixel electrodeis formed on the organic layer, or a method in which the passivationlayer is etched to form an intaglio and then the pixel electrode isformed thereon.

As described above, in the present exemplary embodiment, similar to theaforementioned embodiments, the photosensitive layer which is used asthe partition walls also serves as the mask to pattern the lower layers,so that it is possible to reduce the number of masks and simplify themanufacturing process.

Unlike the aforementioned embodiments, in the present exemplaryembodiment, the surface of the pixel electrode has an embossed shape, sothat, as compared with a flat structure, the embossed structure has alarger emission area in terms of the same aperture ratio, and alight-emission amount per unit pixel may be increased.

Although exemplary embodiments and modified examples of the presentinvention have been described, the present invention is not limited tothe exemplary embodiments and examples, but may be modified in variousforms without departing from the scope of the appended claims, thedetailed description, and the accompanying drawings of the presentinvention. Therefore, it is natural that such modifications belong tothe scope of the present invention.

1. An organic light emitting diode display comprising: a substrate; afirst signal line formed on the substrate; a second signal lineintersecting the first signal line; a plurality of thin film transistorsformed on the substrate and electrically connected to the first andsecond signal lines; a passivation layer formed on the thin filmtransistors; a photosensitive layer formed on the passivation layer andhas a first opening; a first electrode connected to one of the thin filmtransistors and separated from the photosensitive layer; a lightemitting member is formed on the first electrode and is defined by thephotosensitive layer; and a second electrode formed on the lightemitting member.
 2. The organic light emitting diode display of claim 1,wherein the first electrode has an area smaller than that of the firstopening.
 3. The organic light emitting diode display of claim 1, whereina boundary of the first electrode is disposed in the first opening andcontacts the light emitting member.
 4. The organic light emitting diodedisplay of claim 3, wherein the first electrode is disposed inside thefirst opening and is separated from the photosensitive layer by about 1μm to about 5 μm.
 5. The organic light emitting diode display of claim1, wherein one of the thin film transistors and the first electrode haveside contact.
 6. The organic light emitting diode display of claim 5,wherein the first electrode contacts the substrate.
 7. The organic lightemitting diode display of claim 6, wherein at least a portion of thelight emitting member overlaps the thin film transistors.
 8. The organiclight emitting diode display of claim 1, wherein the passivation layeris removed from the first opening.
 9. The organic light emitting diodedisplay of claim 1, wherein portions of the photosensitive layersurrounding the first opening are used as partition walls.
 10. Theorganic light emitting diode display of claim 1, wherein thephotosensitive layer further comprises a second opening, and wherein thelight emitting diode display further comprises a connecting memberconnecting a plurality of thin film transistors, the connecting memberbeing formed in the second opening and separated from the photosensitivelayer.
 11. The organic light emitting diode display of claim 10, furthercomprising a first insulating member on the connecting member.
 12. Theorganic light emitting diode display of claim 10, wherein thepassivation layer is removed from the second opening.
 13. The organiclight emitting diode display of claim 10, wherein the connecting membercontacts the substrate.
 14. The organic light emitting diode display ofclaim 1, wherein the passivation layer and the photosensitive layercomprise a single-layered organic layer.
 15. The organic light emittingdiode display of claim 14, wherein the single-layered organic layercomprises a photo-curable material.
 16. The organic light emitting diodedisplay of claim 1, further comprising a second insulating member formedin the first opening and having a thickness which differs from that ofthe first opening.
 17. The organic light emitting diode display of claim16, wherein the second insulating member comprises the same material asthat of the photosensitive layer.
 18. The organic light emitting diodedisplay of claim 16, wherein the second insulating member comprises atleast one of a concave and a convex portion.
 19. An organic lightemitting diode display comprising: a substrate; a first signal lineformed on the substrate; a second signal line intersecting the firstsignal line; a plurality of thin film transistors formed on thesubstrate and electrically connected to the first and second signallines; an insulating layer formed on the thin film transistors andcomprising a first portion and a second portion thinner than the firstportion, the second portion having at least one of a concave and convexportion; a first electrode formed on the insulating layer; a lightemitting member formed on the first electrode; and a second electrodeformed on the light emitting member.
 20. The organic light emittingdiode display of claim 19, wherein the insulating layer furthercomprises a third portion thinner than the first portion, and the thirdportion is formed on an end portion of at least one of the first andsecond signal lines.
 21. The organic light emitting diode display ofclaim 19, wherein the first portion of the insulating layer has anopening, and a connecting member is formed in the opening, wherein theconnecting member is separated from the insulating layer and connects aplurality of the thin film transistors.
 22. A method of manufacturing anorganic light emitting diode display comprising: forming a plurality ofsignal lines and a plurality of thin film transistors on a substrate;forming a passivation layer on the signal lines and the thin filmtransistors; forming a photosensitive layer having a plurality ofopenings on the passivation layer; etching the passivation layer usingthe photosensitive layer as a mask; forming a first electrode bydepositing a conductive layer on substantially the entire surfaceincluding the photosensitive layer and etching the conductive layer toform the first electrode; forming a light emitting member in portions ofthe openings; and forming a second electrode on the light emittingmember and the photosensitive layer.
 23. The method of claim 22, whereinin the etching of the passivation layer, portions of the thin filmtransistors are exposed.
 24. The method of claim 22, further comprisingforming an insulating member in the portions of the openings after theformation of the first electrode.
 25. The method of claim 24, wherein ashadow mask is used in the formation of the insulating member.
 26. Themethod of claim 22, wherein in the formation of the first electrode, thefirst electrode is formed to be spaced apart from the photosensitivelayer.
 27. The method of claim 22, further comprising curing thephotosensitive layer after the etching of the passivation layer.
 28. Themethod of claim 22, wherein in the formation of the passivation layerand forming the photosensitive layer, the passivation layer and thephotosensitive layer are formed to constitute a single-layered organiclayer.
 29. The method of claim 22, wherein in the etching of thepassivation layer, portions of the photosensitive layer are subject to aslit-process developing.
 30. The method of claim 22, wherein in theformation of the photosensitive layer, the photosensitive layer ispatterned to have a first portion and a second portion thinner than thefirst portion, the second portion having at least one of a concave and aconvex portion.
 31. The method of claim 30, wherein in a slit mask isused in the formation of the photosensitive layer.
 32. The method ofclaim 30, wherein the formation of the photosensitive layer furthercomprises forming a third portion in which the photosensitive layer isremoved, and the method of manufacturing an organic light emitting diodedisplay further comprises the formation of an insulating member in thethird portion after the formation of the first electrode.
 33. A methodof manufacturing an organic light emitting diode display comprising:forming a plurality of signal lines and a plurality of thin filmtransistors on a substrate; forming an organic insulating layer on thesignal lines and the thin film transistors; forming openings whichexpose portions of the thin film transistors by removing portions of theorganic insulating layer; forming a first electrode by depositing aconductive layer on substantially the entire surface including theorganic insulating layer and etching the conductive layer to form thefirst electrode; forming a light emitting member on portions of theopenings; and forming a second electrode on the light emitting memberand the organic insulating layer.
 34. The method of claim 33, furthercomprising forming an insulating member in the portions of the openingsafter the formation of the first electrode.
 35. The method of claim 34,wherein a shadow mask is used in the formation of the insulating member.36. The method of claim 33, wherein in the formation of the firstelectrode, the first electrode is formed apart from the organicinsulating layer.
 37. An organic light emitting diode displaycomprising: a substrate; a first signal line formed on the substrate; asecond signal line intersecting the first signal line; a plurality ofthin film transistors formed on the substrate and electrically connectedto the first and second signal lines; a passivation layer formed on thethin film transistors; partition walls formed on the passivation layerand having a first opening; a first electrode contacting at leastportion of the substrate in the first opening; a light emitting memberformed on the first electrode and defined by the partition walls; and asecond electrode formed on the light emitting member.
 38. The organiclight emitting diode display of claim 37, wherein the first electrodehas an area which is smaller than that of the first opening.
 39. Theorganic light emitting diode display of claim 38, wherein the firstelectrode is disposed inside the first opening and is separated from thepartition walls by about 1 μm to about 5 μm.
 40. The organic lightemitting diode display of claim 37, wherein one of the thin filmtransistors and the first electrode have side contact.
 41. The organiclight emitting diode display of claim 37, wherein the passivation layeris removed from the first opening.
 42. The organic light emitting diodedisplay of claim 37, wherein the partition walls have a second opening,and the light emitting diode display further comprises a connectingmember formed in the second opening which contacts the substrate andconnects a plurality of the thin film transistors.
 43. The organic lightemitting diode display of claim 42, further comprising an insulatingmember on the connecting member.
 44. An organic light emitting diodedisplay comprising: a substrate; a first signal line formed on thesubstrate; a second signal line intersecting the first signal line; aswitching thin film transistor formed on the substrate and connected tothe first and second signal lines; a driving thin film transistorconnected to the switching thin film transistor; a driving voltage lineconnected to the driving thin film transistor; a passivation layerformed on substantially the entire surface of the substrate; aphotosensitive layer formed on the passivation layer and having a firstopening; a first electrode connected to the driving thin film transistorand separated from the photosensitive layer; a light emitting memberformed on the first electrode and defined by the photosensitive layer;and a second electrode formed on the light emitting member.